A number of devices are known in the prior art for stacking and downstacking container ends in a manufacturing plant. One such device for accomplishing both functions is shown in U.S. Pat. No. 3,545,631 to Mojden for "Can End Transfer Apparatus". Such apparatus is suitable for its intended purpose, namely, to arrange individual container ends into a stack or to arrange the stack into individual container ends on a transfer belt. However, such devices are not suitable where means for accumulating container ends is required between two work stations to accommodate stoppages and surges in the supply of container ends or in the utilization thereof. A particular situation where an accumulator is needed is between the shell press and the liners and between the liners and the conversion press in a container end manufacturing plant. The problem in handling individual container ends is that the rolled over peripheral edge has a very small radius and adjacent container ends tend to ride up on each other if there is any lateral force pushing them together. It can be understood that if a number of such container ends are placed in individual side by side relationship on a conveyor and any lateral pressure is exerted against them, they will become interlayed with each other and difficult, if not impossible, to handle in any predetermined, predictable fashion.
U.S. Pat. No. 3,685,671 to Layman for "Stacking Lightweight Plastic Articles" shows apparatus using air jets for stacking plastic trays. U.S. Pat. No. 3,731,823 to Goth for "Wafer Transport System" shows a device for stacking semiconductor wafers.
Apparatus for arranging containers, such as aluminum or steel cans, into single file is shown in my copending U.S. Patent application Ser. No. 533,225, filed Sept. 19, 1983 for "Vertical Single Filer Conveyor System", now Pat. No. 4,561,806 . While this apparatus is entirely suitable for handling containers, it cannot handle individual container ends in side by side relationship because the lateral forces exerted by the converging side walls will cause them to ride up on each other.